JP2002169511A - Luminous device and driving method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a luminous device which has a function of correcting an decrease in luminance of luminous elements in a pixel part and is able to display a uniform screen without uneven luminance. SOLUTION: When a power source is switched on, the luminous device displays a specific test pattern, and detects the luminance by a photoelectric transducing element 106 arranged on each pixel and stores it in a storage circuit 104. Following it, a correction circuit 195 corrects a 1st video signal 101A according to the deficiency from the standard luminance (luminance of a normal luminous element at the same gradation stored beforehand), and obtains a 2nd video signal 101B. A display 108 displays a video using the 2nd video signal 101B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a self-luminous device, and more particularly to an active matrix type self-luminous device. Among them, organic electroluminescence (EL) is particularly used in the pixel section.
The present invention relates to an active matrix type self-luminous device using self-luminous elements including elements.

[0002]

2. Description of the Related Art In recent years, a self-luminous device in which a semiconductor thin film is formed on an insulator such as a glass substrate, particularly an active matrix type self-luminous device using a thin film transistor (hereinafter, referred to as TFT) has become remarkable. An active matrix self-luminous device using TFTs has hundreds of thousands to millions of TFTs in a pixel portion arranged in a matrix, and displays an image by controlling the charge of each pixel. ing.

As a more recent technology, in addition to a pixel TFT constituting a pixel, a technology relating to a polysilicon TFT in which a driving circuit is simultaneously formed using a TFT around a pixel portion has been developed. A self-luminous device has become an indispensable device in a display unit of a mobile device, which greatly contributes to low power consumption and has recently been remarkably expanding its application field.

As a flat display replacing an LCD (liquid crystal display), a self-luminous device using a self-luminous material such as an organic EL has attracted attention, and active research is being conducted.

FIG. 15A schematically shows a typical self-luminous device. In this specification, an organic EL element (hereinafter, simply referred to as an EL element) will be described as an example of a self-luminous element. Insulator (eg, glass) substrate 1501
The pixel portion 1504 is arranged at the center. Pixel section 15
In 04, a current supply line 1505 for supplying a current to the EL element is arranged in addition to the source signal line and the gate signal line. A source signal line driver circuit 1502 for controlling a source signal line is provided above the pixel portion 1504, and a gate signal line driver circuit 1503 for controlling a gate signal line is provided on the left and right of the pixel portion 1504. Have been.
Note that in FIG. 15A, the gate signal line driver circuits 1503 are provided on both left and right sides of the pixel portion; however, they may be provided only on one side. However, it is desirable from the viewpoint of driving efficiency and reliability to dispose both sides. A signal is input to the source signal line driver circuit 1502 and the gate signal line driver circuit 1503 from a flexible print circuit (Flexible Print Circuit: FPC) from the outside.
This is performed via 1506.

FIG. 15B is an enlarged view of a portion surrounded by a dotted frame 1500 in FIG. In the pixel section, each pixel is arranged in a matrix as shown in FIG. In FIG. 15B, a portion further surrounded by a dotted line frame 1510 is one pixel, and a source signal line 1511, a gate signal line 1512, a current supply line 1513, a switching T
FT1514, EL driving TFT 1515, storage capacitor 1
516, an EL element 1517, and the like.

Next, the operation of the active matrix type self light emitting device will be described with reference to FIG.
First, when the gate signal line 1512 is selected, a voltage is applied to the gate electrode of the switching TFT 1514,
The switching TFT 1514 is turned on. Then, a signal (voltage signal) of the source signal line 1511 is accumulated as charge in the storage capacitor 1516. Storage capacity 1516
The EL drive TFT 1515
Of the gate-source voltage V _GS of the storage capacitor 151 is determined.
The current corresponding to the voltage of the EL drive TFTs 1515 and E
It flows to the L element 1517. As a result, the EL element 1517
Emits light.

The luminance of the EL element 1517, that is, the amount of current flowing through the EL element 1517 is determined by the EL driving TFT 1515.
Equal to the amount of current flowing between the source and drain, it can be controlled by V _GS of the EL driving TFT TFT1515. V
_GS is the voltage of the storage capacitor 1516, which is the signal (voltage) input to the source signal line 1511. That is, the luminance of the EL element 1517 is controlled by controlling a signal (voltage) input to the source signal line 1511. Finally, the gate signal line 1512 is set to a non-selected state, the gate of the switching TFT 1514 is closed, and the switching TFT 1514 is turned off. At that time, the charge accumulated in the storage capacitor 1516 is held.
Therefore, the V _GS of the EL driving TFT 1515 is maintained as it is, and a current corresponding to the V _GS is supplied to the EL driving TFT 1515.
15 and continue to flow to the EL element 1517.

Regarding the driving of the EL element, etc., SID99 Dige
st: P372: "Current Status and future of Light-Emi
tting Polymer Display Driven by Poly-Si TFT ", ASIA
DISPLAY98: P217: "High Resolution Light Emitting
Polymer Display Driven byLow Temperature Polysili
con Thin Film Transistor with Integrated Driver ",
Euro Display99 Late News: P27: "3.8 Green OLED wi
th Low Temperature Poly-Si TFT ".

Next, a method of gradation display of the EL element 1517 will be described. The EL driving TFT 15 as described above.
EL element 15 by the gate-source voltage V _GS of 15
The analog gray scale method for controlling the luminance of the pixel 17 has a drawback that the current characteristic of the EL driving TFT 1515 is weak. That is, if the current characteristics of the EL driving TFT 1515 are different, the current flowing through the EL driving TFT 1515 and the EL element 1517 will change even if the same gate voltage is applied. As a result, the luminance of the EL element 1517, that is, the gradation changes.

In order to reduce the influence of the characteristic variation of the EL driving TFT 1515 and obtain a uniform screen,
A method called a digital gradation method has been devised. In this method, when the absolute value | V _GS | of the gate-source voltage of the EL driving TFT 1515 is equal to or lower than the lighting start voltage (almost no current flows), and when the absolute value | V _GS | This is a method of controlling the gradation in two states of “flowing”. In this case, the EL driving TF
T1515 of | V _GS | a if sufficiently larger than the brightness saturation voltage, even if variations in current characteristics of the EL driving TFT1515, the current value becomes close to I _MAX. Therefore, EL
The influence of variations in the driving TFT 1515 can be extremely reduced. As described above, since the gray scale is controlled in two states of the ON state (bright because the maximum current flows) and the OFF state (dark because no current flows), this method is called a digital gray scale method. ing.

However, in the case of the digital gradation method,
With this method, only two gradations can be displayed. Therefore, a plurality of techniques for increasing the number of gradations in combination with another method have been proposed.

One of the methods for increasing the number of gradations is a time gradation method. The time gray scale method is a method in which the time during which the EL element 1517 is lit is controlled, and a gray scale is output according to the length of the lit time. That is, one frame period is divided into a plurality of sub-frame periods, and the number and length of the lit sub-frame periods are controlled to express gradation.

Referring to FIG. FIG. 9 schematically shows a timing chart of the time gray scale method. In this example, a frame frequency is set to 60 [Hz], and a 3-bit gray scale is obtained by a time gray scale method.

As shown in FIG. 9A, one frame period
Is divided into sub-frame periods corresponding to the number of gradation bits. This
Here, since there are three bits, three subframe periods S
F₁~ SF_ThreeIs divided into One subframe period
Is the address period (Ta_#) And sustain (dot)
Light) period (Ts_#) (FIG. 20B). S
F ₁The sustain period at Ts₁I will call it. SF
_Two, SF_ThreeSimilarly, in the case of_Two, Ts_ThreeCall
I will. Address period Ta₁~ Ta_ThreeIs 1
This is the period during which video signals for frames are written to the pixels.
And the lengths are equal in any subframe period.
No. The sustain period here is Ts₁: Ts_Two: Ts_Three
= 2^Two: 2¹: 2⁰= 4: 2: 1, power of 2
It has a power ratio.

As a method of gradation display, Ts ₁ to Ts ₃
In the sustain (lighting) period up to the above, the luminance is controlled by controlling the length of the total lighting time within one frame period by controlling the EL element to be turned on or off. In this example, as shown in FIG. 9B, 2 ³ = 8 different lighting time lengths can be determined by a combination of the sustaining (lighting) periods for lighting, so that 0 (all black display). Eight gradations of up to 7 (all white display) can be displayed. In the time gradation method, gradation expression is performed as described above. Needless to say, the same gradation expression is possible in a self-luminous device for color display.

When the number of gradations is further increased, the number of divisions in one frame period may be increased. One frame period
When the period is divided into n subframes, the ratio of the length of the sustain (lighting) period is Ts ₁ : Ts ₂ :
_{Ts (n-1): Ts} n = 2 (n-1): 2 (n-2): ·····
2 ¹ : 2 ⁰ , which makes it possible to express 2 ⁿ gradations. The order of the subframe periods is SF _{1 to} S
Until the F _n may be to appear at random. In addition,
Even if the ratio of the length of the sustain (lighting) period is not necessarily set to a power of 2, gradation expression is possible.

[0018]

A problem concerning a self-luminous device using a self-luminous element such as an EL element will be described. As described above, the current is always supplied during the period in which the EL element is lit, and the current flows in the EL element. As a result, the characteristics of the EL element itself deteriorate due to long-time lighting, and the luminance characteristics change due to this. That is, even if current is supplied at the same voltage from the same current supply source, a difference occurs between the deteriorated EL element and the undegraded EL element.

A specific example will be described. FIG. 10 (A)
Is a display screen of a portable terminal device or the like using a self-luminous device, on which icons 1001 for operation and the like are displayed. Normally, in the use of such equipment, FIG.
The ratio of the still image display as shown in FIG. At this time, if an icon or the like is displayed in a color (gradation) brighter than the background, the EL element in the pixel where the icon or the like is displayed lights for a longer time than the EL element in the background display part. Therefore, the deterioration proceeds more quickly.

It is assumed that the EL element has deteriorated under such conditions. FIG. 10B shows a display example of the self-luminous device after deterioration.
It is shown in (C). First, in the case of a black display as shown in FIG. 10B, self-luminous elements such as EL elements express black by applying no voltage to the elements, that is, by turning off the EL elements. Therefore, when black is displayed, the deterioration hardly causes a problem. However, in the case of a white display, even if the same current is supplied to the EL element deteriorated by long-time lighting (in this case, the EL element in which an icon or the like is displayed), FIG. In this case, as shown by reference numeral 1011, the luminance is insufficient and unevenness occurs.

To solve this luminance unevenness, the deteriorated E
There is a method of increasing the voltage applied to the L element, but usually, in the self-luminous device, the current supply line is formed by a single wiring, and a specific one of the current supply lines is arranged in a matrix.
It is not easy to configure a circuit for changing a voltage applied to an EL element in a pixel in a pixel portion. Further, as described above, such a correction method is not desirable because there are variations in the EL driving TFTs and the like.

As a method for solving the above problem, there is a technique described in Japanese Patent Application No. 2000-273139.
This will be briefly described below with reference to FIG.

FIG. 18 is a schematic view of a self-luminous device having a deterioration correction function described in Japanese Patent Application No. 2000-273139. According to this method, the lighting time of each pixel or the lighting time and the lighting intensity are determined by the first video signal 18.
01A is detected by sampling periodically by the counter 1802 and stored in the memories 1803 and 1804. A video signal for driving a pixel having a deteriorated EL element is corrected by referring to the accumulation of the detected value and data on the change over time in the luminance characteristic of the EL element stored in the correction data storage unit 1806 in advance. The second video signal 1801B is obtained by correction by calculation in the circuit 1805. An image is displayed using the second image signal 1801B. As a result, luminance unevenness in the display device 1807 in which the EL elements in some pixels have deteriorated is corrected,
It says that a uniform screen can be obtained.

However, according to the above-described method, the state of deterioration of the EL element at a certain point in time is not directly detected, and the state of deterioration is determined from the cumulative lighting time of the element or the cumulative lighting time and the lighting intensity. Estimated.
The lighting intensity here is obtained not by the lighting intensity of the EL element itself but by reading the gradation of the input digital video signal, and the video signal is corrected in accordance with the correction data prepared in advance. That is, there is a drawback that deterioration not caused by the driving time cannot be dealt with. For example, a decrease in luminance caused by deterioration due to a temperature change, etc.
This cannot be done by counting only the cumulative lighting time. Also,
Luminance failure due to initial characteristic variation of the element itself also
The above method cannot cope.

[0025]

Accordingly, in the present invention, a state of deterioration is detected by a method not depending on the cause of the deterioration of the EL element, and the video signal is corrected so that uniform screen display without luminance unevenness can be performed for a long time. It is intended to provide a possible self-luminous device.

[0026]

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention takes the following measures.

In the self-luminous device having a luminance correction function of the present invention, each pixel has an EL element and a photoelectric conversion element, and the luminance of the EL element being displayed at a certain gradation is allocated to each pixel. It is detected by the photoelectric conversion element that has been used. Subsequently, the shortage of luminance is calculated by comparing the value detected by the photoelectric conversion element with the reference luminance at the same gradation of the EL element stored in advance, and the correction circuit calculates the gradation data of the video signal. Is input to the display device after the correction is performed. The display device displays an image based on the corrected image signal. With the above method, uniform display can be maintained without causing luminance unevenness even in a self-luminous device in which an EL element has a luminance defect.

The structure of the self-luminous device of the present invention will be described below.

A first feature of the self-luminous device according to the present invention is that, in a self-luminous device for inputting a video signal and displaying an image, means for detecting the luminance of the self-luminous element of each pixel and storing the luminance Means, and means for correcting the video signal according to the stored luminance, wherein a video is displayed using the corrected video signal.

A second feature of the self-luminous device of the present invention is that, in a self-luminous device for inputting a video signal and displaying an image, a photoelectric conversion element for detecting the luminance of the self-luminous element of each pixel; A storage circuit for storing the luminance of the self-luminous element of each pixel detected by the element, and correcting the first video signal in accordance with the stored luminance of the self-luminous element of each pixel to produce a second video It is characterized by including a luminance correction device having a signal correction unit that outputs a signal, and a display device that displays an image using the second image signal.

A third feature of the self-luminous device of the present invention is that in a self-luminous device for inputting a video signal and displaying a video, the luminance of the self-luminous element of each pixel is detected. k
Is a natural number), a memory for storing the luminance of the self-luminous element of each pixel detected by the photoelectric conversion element, and a first memory according to the stored luminance of the self-luminous element of each pixel. A luminance correction device including a signal correction unit that corrects a video signal and outputs a second video signal; a display device including j × k pixels that displays a video using the second video signal; It is characterized by having.

A fourth feature of the self-luminous device of the present invention is that, in the self-luminous device of the present invention, n bits (n is a natural number, n ≧ n)
2) A self-luminous device that performs grayscale display has n + m bits (m
The pixel having a driving circuit for performing signal processing of (a natural number) and having a self-luminous element that does not cause a decrease in luminance displays a gradation by an n-bit video signal, and emits light with a decrease in luminance. In the pixel having the element, by correcting the video signal using the m-bit signal with respect to the n-bit video signal, the self-luminous element in which the brightness is not reduced and the brightness in the pixel are reduced. It is characterized in that the same brightness is obtained with the self-luminous element.

A fifth feature of the self-luminous device according to the present invention is that, in the self-luminous device according to the present invention, the correcting means includes a video signal written to a pixel having a self-luminous element having a reduced luminance, the luminance of which is lower than the luminance of the video signal. It is characterized in that an addition process is relatively performed on a video signal written to a pixel having a self-luminous element in which no decrease has occurred.

A sixth feature of the self-luminous device according to the present invention is that, in the self-luminous device according to the present invention, the correcting means detects a pixel having a self-luminous element having a small decrease in luminance or a decrease in luminance within a display range. A video signal written to a pixel having a self-luminous element that does not generate is subjected to a relative subtraction process with respect to a video signal written to a pixel having a self-luminous element having the largest decrease in luminance.

According to a seventh feature of the self-luminous device of the present invention, in the self-luminous device of the present invention, the storage means uses a static memory circuit (SRAM).

An eighth feature of the self-luminous device of the present invention is that in the self-luminous device of the present invention, the storage means uses a dynamic memory circuit (DRAM).

A ninth feature of the self-luminous device of the present invention is that in the self-luminous device of the present invention, the storage means uses a ferroelectric memory circuit (FeRAM).

A tenth feature of the self-luminous device of the present invention is that, in the self-luminous device of the present invention, the storage means is a nonvolatile memory (EE) capable of electrically writing, reading, and erasing.
(PROM).

An eleventh feature of the self-luminous device of the present invention resides in that in the self-luminous device of the present invention,
A PN type photodiode is used as the photoelectric conversion element.

A twelfth feature of the self-luminous device of the present invention is that, in the self-luminous device of the present invention,
A PIN type photodiode is used for the photoelectric conversion element.

A thirteenth feature of the self-luminous device of the present invention is that, in the self-luminous device of the present invention, the brightness detecting means includes:
An avalanche photodiode is used as the photoelectric conversion element.

According to a fourteenth feature of the self-luminous device of the present invention, in the self-luminous device of the present invention, the detecting means, the storing means, and the correcting means are constituted by circuits external to the self-luminous device. It is characterized by being done.

A fifteenth feature of the self-luminous device of the present invention is that, in the self-luminous device of the present invention, the detecting means, the storing means, and the correcting means are provided on the same insulator as the self-luminous device. It is characterized by being formed in.

A sixteenth feature of the self-luminous device of the present invention is that in the self-luminous device of the present invention, the self-luminous device is an EL display.

A seventeenth feature of the self-luminous device of the present invention is that in the self-luminous device of the present invention, the self-luminous device is a PDP display.

An eighteenth feature of the self-luminous device of the present invention is that in the self-luminous device of the present invention, the self-luminous device is an FED display.

The first feature of the method for driving a self-luminous device of the present invention is a method for driving a self-luminous device for displaying an image by inputting a video signal, wherein the luminance of the self-luminous element of each pixel is detected. Storing the detected brightness of the self-luminous element of each pixel,
The first video signal is corrected in accordance with the difference between the stored luminance of the self-luminous element of each pixel and the reference luminance, a second video signal is output, and the second video signal is output. It is characterized by displaying images.

A second feature of the method for driving a self-luminous device according to the present invention is a method for driving a self-luminous device for displaying an image by inputting a video signal. The luminance is detected, the luminance of the self-luminous element of each pixel detected by the photoelectric conversion element is stored in the storage circuit, and stored in the storage circuit, the luminance of the self-luminous element of each pixel and the reference luminance. The first video signal is corrected in the signal correction unit in accordance with the difference between the two, a second video signal is output, and a video is displayed using the second video signal.

A third feature of the method for driving a self-luminous device according to the present invention is that, in the method for driving a self-luminous device according to the present invention, a self-luminous device for displaying n bits (n is a natural number, n ≧ 2) gradations Has a drive circuit that performs signal processing of n + m bits (m is a natural number), and a pixel having a self-luminous element that does not cause a decrease in luminance performs grayscale display with an n-bit video signal, A pixel having a reduced self-luminous element, for the n-bit video signal, by correcting the video signal using an m-bit signal, a self-luminous element that does not reduce the brightness, The present invention is characterized in that the same brightness is obtained from the self-luminous element in which the brightness has decreased.

A fourth feature of the method of driving a self-luminous device of the present invention is that, in the method of driving a self-luminous device of the present invention, the correction means is written to a pixel having a self-luminous element which has reduced luminance. The video signal is characterized in that an addition process is performed relatively to a video signal written to a pixel having a self-light-emitting element in which luminance does not decrease.

A fifth feature of the driving method of the self-luminous device of the present invention is that, in the driving method of the self-luminous device of the present invention, the correction means has a self-luminous element having a small decrease in luminance within a display range. For a video signal written to a pixel or a pixel having a self-luminous element that does not cause a decrease in luminance, a relative subtraction process is performed on a video signal written to a pixel having a self-luminous element having the largest decrease in luminance. It is characterized by:

[0052]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. FIG. 1 is a block diagram of a self-luminous device having a brightness correction function according to the present invention. The luminance correction device that is the basis of the present invention includes a storage circuit unit 100, a correction circuit 105, a photoelectric conversion element 106, and the like. The storage circuit unit 100 includes a correction data storage unit 10
2. It has a storage circuit 104 for storing the test pattern 103 and the like and for storing the detected luminance. The photoelectric conversion element 106 is arranged so as to overlap a part of the light emitting surface of the self light emitting element 107. Here, when the size of the photoelectric conversion element 106 is large, the light emitting surface of the self-light emitting element 107 is pressed, so that the size is desirably as small as possible. Since the signal after photoelectric conversion of the light emitted from the self-luminous element 107 becomes weak, the voltage amplitude is obtained via an amplifier circuit such as an operational amplifier.

FIG. 14A is a circuit diagram of a source signal line driver circuit in the display device 108. Here, a display device corresponding to a digital video signal is taken as an example. The source signal line driver circuit includes a shift register (SR) 1401,
A first latch circuit (LAT1) 1402, a second latch circuit (LAT2) 1403, and the like are provided. Reference numeral 1404 denotes a pixel, and 1405 denotes the luminance correction device shown in FIG.

The operation of each section will be described. According to a clock signal (CLK) and a start pulse (SP),
Sampling pulses are sequentially output from the shift register. The first latch circuit holds the digital video signal in accordance with the timing of the sampling pulse. FIG.
As shown in FIG. 4A, the video signal has already been corrected at this point, and is now the second video signal. When the holding of one horizontal period is completed in the first latch circuit, a latch pulse is output, and the transfer of the digital video signal to the second latch circuit is performed. After that, writing to the pixel is performed from the second latch circuit. At the same time, according to the sampling pulse from the shift register again, the first
Holds the digital video signal.

Next, the operation of the entire luminance correction device will be described. First, with respect to the EL element used in the self-luminous device, the luminance with respect to the input of a certain gradation signal is stored in advance in the correction data storage unit 102 as the reference luminance. The EL element of each pixel corrects a video signal according to the deviation from the reference luminance. Further, the reference luminance need not be limited to a certain gradation, and the reference luminance may be stored for each of a plurality of gradations.

Next, the test pattern is input to the display device, and the screen is displayed. At this time, the test pattern is desirably a plain halftone display or a white display. And
The above-described reference luminance is the reference luminance at that gradation. In the correction data storage unit 102, in addition to the reference luminance,
The amount of change in luminance per gradation at a certain bit number is also stored. The result detected here is temporarily stored in the storage circuit 104. Thereafter, according to the test pattern, while the EL element is turned on in the pixel portion, the luminance is detected by a photoelectric conversion element provided in each pixel. For example, when a certain EL element is deteriorated for some reason, its luminance usually decreases. Therefore, there is a difference in luminance between the detected luminance and the reference luminance even in the case of display using the same gradation signal. The difference in the luminance is calculated for the number of gray levels of the digital video signal currently being used, and the first video signal 101A is corrected for each pixel by that gray level to obtain the second video signal 101B. And input it to the display device.

As a configuration of the storage circuit unit 100, a nonvolatile memory such as a flash memory must be used for the correction data storage unit 102 and the test pattern 103. As described above, the volatile detection circuit may be used for the storage circuit 104 because the luminance detection result is constantly updated each time the power is turned on. Volatile memories include static memory (SRAM), dynamic memory (DRAM), and ferroelectric memory (FRA).
M) etc. may be used. Note that the structure of these storage circuits is not particularly limited in the present invention.

The procedure for detecting the luminance by the photoelectric conversion element 106 is desirably to always detect it during normal image display, update the storage circuit 104, and correct the video signal in real time. Considering the actual operation of 106, it is difficult in terms of time, so one method is to perform the above-described series of operations when the power of the self-luminous device is turned on. Needless to say, if a photoelectric conversion element having a fast response can be used, the first video signal and the luminance detected in real time during the display of the video obtained by inputting the first video signal can be obtained. By comparing the two, it is possible to know the degree of reduction in the luminance of the EL element, so that the correction operation can be performed during the display of an image.

The photoelectric conversion element used in the self-luminous device of the present invention is required to have minuteness, high-speed response, stability, linearity with respect to incident light, high detection sensitivity, and the like. From these requirements, it is desirable to use a photodiode in the self-luminous device of the present invention. In particular, a PN junction photodiode and a PIN junction photodiode will be described later in Examples, but they are particularly preferable because they can be easily formed in a process and can be minutely formed. In addition,
Other photodiodes include avalanche photodiodes and the like. In the present invention, any of these photodiodes may be used.

Further, in the figure shown in the present embodiment, the switch 113 is used for switching between the input of the test pattern and the input of the ordinary digital video signal. However, the present invention is not limited to this, and another method may be used.

[0061]

Embodiments of the present invention will be described below.

[Example 1]

As one of the methods for correcting the insufficient luminance of the deteriorated EL element at the video signal level, a correction value in the input digital video signal is added and converted into a signal substantially several gradations higher. By doing, normal EL
There is a method of achieving luminance equivalent to that of the element. The easiest way to achieve this in circuit design is to prepare a circuit capable of processing additional grayscales in advance. Specifically, for example, in the case of a self-luminous device having a 6-bit digital gradation (64 gradations) specification having a luminance correction function of the present invention, a processing capability of 1 bit is added as an additional for correction. It is designed and created as a substantial 7-bit digital gray scale (128 gray scales). In normal operation, the lower 6 bits are used, and when the EL element is deteriorated, it is corrected to a normal digital video signal. The value is added, and the signal processing for the added value is performed using the above-mentioned additional 1 bit. In this case, the most significant bit (Most Significant Bi
t: MSB) is used only for signal correction, and the actual display gradation is 6 bits.

[Embodiment 2] In this embodiment, Embodiment 1
A method of correcting a digital video signal different from the above will be described.

Referring to FIG. 1 and FIG. FIG. 2 (A)
Indicates a part of the pixel of the display device 108 in FIG. Note that, for simplicity, the photoelectric conversion elements arranged in the pixel portion are not illustrated here.

Here, three pixels 201 to 203 are considered. First, it is assumed that the pixel 201 is a pixel in which no deterioration has occurred, and that the pixels 202 and 203 each have some degree of deterioration. At this time, assuming that the degree of deterioration is greater in the pixel 203 than in the pixel 202,
As a matter of course, the decrease in luminance due to the deterioration also increases. That is, when a certain halftone is displayed, luminance unevenness occurs as shown in FIG. The luminance of the pixel 202 is lower than the luminance of the pixel 201, and the luminance of the pixel 203 is lower.

Next, the actual correction operation will be described.
First, the correction of the luminance by the addition processing will be described.

First, an EL illuminated by a certain gradation signal
The luminance of the element is measured in advance, and the reference luminance and the luminance change amount per one gradation of a certain digital video signal are stored in the correction data storage unit 102. Subsequently, display is performed using a certain test pattern, and the luminance of each pixel in the screen is detected by the photoelectric conversion element 106 and converted into a signal. The detection result of the reference luminance and the luminance of each pixel is input to the correction circuit 105. At this time,
The detection result of the luminance of each pixel is temporarily stored in the storage circuit 104.
And then input to the correction circuit 105 by reading.

After that, the correction circuit 105 performs an operation from the input numerical values, determines the correction amount of the digital video signal to be written to each pixel, and actually performs the correction. An example is shown in FIG. Here, the pixel 2
01 is B ₁ , the pixel 202 is B ₂ , and the pixel 203 is
The brightness of were B _3. The correction width of the digital video signal, the reference luminance (A) and detection brightness (B ₁ ~B ₃₎
Is obtained by dividing the difference by the luminance change amount (X) per unit gradation. Here, FIG.
As shown in (C), the correction amount of the pixel 201 is “0”,
The correction amount is “1” for the pixel 202 and “2” for the pixel 203. When the difference in luminance is within one gradation, the correction amount is determined by approximating each. In this case, for example, 0.5
With the luminance of the gradation as a boundary, round-up or round-down may be selected, or unified processing may be performed.

The first video signal 101A input to the correction circuit 105 determines the correction width of each pixel by the above-described method, and corrects the luminance by sequentially adding the correction signal to the gradation signal. As shown in FIGS. 2D and 2E, the digital video signal input to each pixel is added with a gradation by the calculated correction width to obtain a luminance equivalent to that of a normal EL element. The second video signal 101B that has been corrected in this way is input to the display device 108 to display a video.

Next, a correction method by a subtraction process will be described. Please refer to FIG. 1 and FIG. 3 (A) and 3 (B) are the same as FIGS. 2 (A) and 2 (B), and a description thereof will be omitted.

As in the above-described addition processing, the luminance of each pixel is
Detected by photoelectric conversion element
Read the road and correct the digital video signal. This and
In this case, the reference luminance is used to determine the most
The brightness at the pixel (the lowest brightness)
is there. With respect to the reference luminance C, the luminance of the pixel 301 is
B ₁, The luminance of the pixel 302 is B_Two, The luminance of the pixel 303 is B_Three
Assume that Here, the correction width of the digital video signal
Is the reference luminance (C) and the detected luminance (B ₁
~ B_Three), And calculate the difference in brightness per unit gradation.
It is obtained by dividing by the conversion amount (X). As shown in FIG.
As described above, in the pixel 301, the correction amount is “−2” and the pixel 30
2, the correction amount is “−1”, and for the pixel 303, the correction amount is “0”.
Becomes If the difference in luminance is within one gradation, approximate each
To determine the correction amount. In this case, for example, for 0.5 gradation
Select whether to round up or down using the brightness of
May be used, or perform unified processing for any of them.
Is also good.

The first video signal 101A input to the correction circuit 105 determines the correction width of each pixel by the above-described method, and sequentially lowers the gray level of the digital video signal by the correction amount from the gray level signal. Correct the brightness. FIG.
(D) As shown in (E), the gradation is reduced from the digital video signal input to each pixel by the obtained correction width, and the luminance is suppressed to the same level as the EL element with the lowest luminance. Can be The second video signal 101B that has been thus corrected is input to the display device 108.

However, when the correction is performed by the above-described means, the brightness of the entire screen is several gradations (the gradation by the original digital video signal and the second video signal written to the pixel in which the EL element is not deteriorated). ). Therefore, at the same time, FIG.
(D), the by changing the potential of the current supply line, a voltage V _EL between two poles of the EL element oblige slightly higher _{(V EL1 + δ → V EL2} ) to correct the brightness of the entire screen by As a result, a normal and uniform screen is obtained as shown in FIG.

In the former case of the correction by the addition processing, it is possible to correct the luminance unevenness only by processing the digital video signal, while the correction in the white display is not effective (specifically, for example, a 6-bit digital video). When "111111" is input as a signal, further addition cannot be performed.) In addition, in the latter case of the correction by the subtraction processing, the potential control of the current supply line for the luminance correction is added. However, contrary to the correction by the addition processing, the range in which the correction is not effective is the range of the black display. There is no influence (specifically, for example, when “000000” is input as a 6-bit digital video signal, there is no need to perform any further subtraction, and an accurate difference between the normal EL element and the deteriorated EL element can be obtained. It is possible to perform black display (the EL element may simply be turned off), and there is a feature that several gradations near black have almost no problem if the corresponding bit number of the display device is high to some extent. Both are methods that are advantageous for increasing the number of gradations.

For example, it is also an effective means to compensate for both disadvantages by using both correction methods of addition processing and subtraction processing at a certain gradation as a boundary.

On the other hand, once the power is turned on to display the test pattern and the luminance of each pixel is detected, the input system of the video signal is switched to a normal one (in the example of this specification,
This is performed by the switch 113 shown in FIG. 1), and a video image is displayed by inputting a digital video signal.

[Embodiment 3] The details of the display device 108 in the schematic diagram shown in FIG. 1 will be described with reference to FIG. FIG.
4A is a schematic diagram of the entire display device, and FIG. 4B is an equivalent circuit diagram of a pixel portion. In FIG. 4A, a pixel portion 405 is provided in the center of a substrate 400. Pixel section 40
5 will be described later, pixels 406 each having an EL element and a photoelectric conversion element are arranged in a matrix. Around the pixel portion 405, an EL source signal line driving circuit 401, an EL gate signal line driving circuit 402, a photoelectric conversion element signal line driving circuit 403, and a photoelectric conversion element scanning line driving circuit 404 are arranged. . In the present embodiment, each driving circuit is arranged one by one around the pixel portion. For example, the EL source signal line driving circuit 401 and the photoelectric conversion element signal line driving circuit 403, or the EL gate signal line driving Circuit 402 and scanning line driving circuit 404 for photoelectric conversion elements
May be integrated in a single circuit and arranged on both sides facing the pixel portion. The supply of signals and power to each drive circuit is performed through the FPC 407.

FIG. 4B is an enlarged view of the pixel 406. One pixel includes a source signal line 411, a gate signal line 412, a switching TFT 413, an EL driving TFT 414, a storage capacitor 415, an EL element 416, a current supply line 417, a signal output line 418, and a reset signal line 41.
9, scanning line 420, reference power supply line 421, reset TF
T422, buffer TFT 423, selection TFT42
4. It is configured by the photoelectric conversion element 425. here,
The storage capacitor 415 is provided to hold electric charge given to the gate electrode of the EL driving TFT 414, but is not necessarily provided.

Since the lighting of the EL element has been described above, it is omitted here. Only the operation around the photoelectric conversion element at the time of luminance detection in each pixel will be described. Scan line 420
, The selection TFT 424 is turned on. In this state, the photoelectric conversion element 425 is provided with EL
Light from the element 416 enters and the buffer TFT 423
Is conducted according to the charge accumulated in the photoelectric conversion element 425, is converted into an electric signal corresponding to the luminance, and is output to the signal output line 418. After that, the signal line driving circuit 40
In 3, the signal is amplified using a buffer, an operational amplifier, etc.
Obtained as a voltage signal. After that, the data is read into a correction circuit through means such as A / D conversion.

[Embodiment 4] In the self-luminous device having the brightness correction function of the present invention, in the example shown in the embodiment (FIG. 1), the brightness correction device is placed outside the display device 108 and the digital video signal The (first video signal) 101A is first input to the correction circuit 105 and immediately corrected, and the corrected digital video signal (second video signal) 101B is input to the display device 108 via the FPC. . Advantages of such a method include high compatibility and good applicability due to unitization of each device. On the other hand, the brightness correction device and the display device are integrally formed on the same substrate. In addition, cost reduction, space saving, and high-speed driving can be realized by greatly reducing the number of parts. here,
Although the layout on the substrate is not particularly shown, it is desirable to arrange the blocks close to each other in consideration of the arrangement of signal lines and the like, the wiring length, and the like.

[Embodiment 5] In this embodiment, a pixel portion of the self-luminous device of the present invention and a driving circuit portion provided around the pixel portion (source signal line side driving circuit, gate signal line side driving circuit, pixel selection signal line A method for simultaneously manufacturing TFTs of the side driver circuit) will be described. However, for the sake of simplicity, a CMOS circuit, which is a basic unit for the drive circuit unit, is illustrated.

Referring to FIG. First, in this embodiment, a substrate 50 made of glass such as barium borosilicate glass represented by Corning # 7059 glass or # 1737 glass or aluminoborosilicate glass is used.
00 is used. Note that the substrate 5000 is not limited as long as it has a light-transmitting property, and a quartz substrate may be used. Further, a plastic substrate having heat resistance enough to withstand the processing temperature of this embodiment may be used.

Next, a base film 5001 made of an insulating film such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film is formed over the substrate 5000. In this embodiment, the base film 5001 is used.
Is used, a single-layer film of the insulating film or a structure in which two or more layers are stacked may be used. Base film 500
As the first layer of the first method, a plasma CVD
₄ , a silicon oxynitride film 5001a formed using NH ₃ and N ₂ O as reaction gases is formed in a thickness of 10 to 200 [nm] (preferably 50 to 100 [nm]). In this embodiment, the film thickness 50
[nm] silicon oxynitride film 5001a (composition ratio Si = 32
[%], O = 27 [%], N = 24 [%], H = 17 [%]. Next, as the second layer of the base film 5001,
Using a plasma CVD method, a silicon oxynitride film 5001b formed using SiH ₄ and N ₂ O as a reaction gas is reduced to 50 to 50%.
The layer is formed to a thickness of 200 [nm] (preferably 100 to 150 [nm]). In this embodiment, a silicon oxynitride film 5001b having a thickness of 100 nm (composition ratio: Si = 32%, O = 59)
[%], N = 7 [%], H = 2 [%]).

Then, the semiconductor layers 5002 to 5
004 is formed. The semiconductor layers 5002 to 5004 are formed by forming a semiconductor film having an amorphous structure by a known means (sputtering method,
After forming a film by LPCVD or plasma CVD, a known crystallization treatment (laser crystallization, thermal crystallization, or thermal crystallization using a catalyst such as nickel) is performed. The formed crystalline semiconductor film is patterned and formed into a desired shape. The semiconductor layers 5002 to 50
04 is 25 to 80 [nm] (preferably 30 to 60 [nm])
Formed with a thickness of Without limitation on the material of the crystalline semiconductor film, preferably silicon (silicon) or silicon germanium _{(Si X Ge 1-X (} X = 0.0001~0.0
2)) It is good to form with an alloy etc. In this example, after a 55 [nm] amorphous silicon film was formed by a plasma CVD method, a solution containing nickel was held on the amorphous silicon film. After dehydrogenation (500 [° C.], 1 hour) of this amorphous silicon film, thermal crystallization (550 [° C.], 4 hours) is performed, and laser annealing for further improving crystallization is performed. Then, a crystalline silicon film was formed by performing a heat treatment. Then, semiconductor layers 5002 to 5004 were formed from the crystalline silicon film by a patterning process using a photolithography method.

After the formation of the semiconductor layers 5002 to 5004, a small amount of impurity element (boron or phosphorus) may be doped in order to control the threshold value of the TFT.

When a crystalline semiconductor film is formed by a laser crystallization method, a pulse oscillation type or continuous emission type excimer laser, a YAG laser, or a YVO ₄ laser can be used. In the case of using these lasers, it is preferable to use a method in which laser light emitted from a laser oscillator is linearly condensed by an optical system and irradiated on a semiconductor film. The crystallization conditions are appropriately selected by the practitioner. When an excimer laser is used, the pulse oscillation frequency is 30 [Hz], and the laser energy density is 100 to 40.
0 [mJ / cm ² ] (typically 200 to 300 [mJ / cm ² ]). When a YAG laser is used, its second harmonic is used to set the pulse oscillation frequency to 1 to 10 kHz and the laser energy density to 300 to 600 [mJ / cm ² ] (typically 350 to 500 [mJ / cm ^2]. ]) Then, a laser beam condensed linearly with a width of 100 to 1000 [μm], for example, 400 [μm] is irradiated over the entire surface of the substrate, and the superposition rate (overlap rate) of the linear laser light at this time is 50. What is necessary is just to carry out as -90 [%].

Next, a gate insulating film 5005 covering the semiconductor layers 5002 to 5004 is formed. Gate insulating film 50
Reference numeral 05 denotes an insulating film containing silicon with a thickness of 40 to 150 [nm] using a plasma CVD method or a sputtering method. In this embodiment, 110 [nm] is obtained by the plasma CVD method.
Silicon oxynitride film (composition ratio Si = 32 [%], O =
59 [%], N = 7 [%], H = 2 [%]). Needless to say, the gate insulating film 5005 is not limited to the silicon oxynitride film, and another insulating film containing silicon may be used as a single layer or a stacked structure.

When a silicon oxide film is used, TEOS (Tetraethyl Orthosilicate) is formed by a plasma CVD method.
And O ₂ , a reaction pressure of 40 [Pa] and a substrate temperature of 300
To 400 [° C.] and discharge at a high frequency (13.56 [MHz]) power density of 0.5 to 0.8 [W / cm ₂ ]. The silicon oxide film thus manufactured can obtain good characteristics as a gate insulating film by subsequent thermal annealing at 400 to 500 [° C.].

Next, a film having a thickness of 2
A first conductive film 5006 having a thickness of 0 to 100 [nm];
A second conductive film 5007 of about 400 [nm] is formed by lamination. In this embodiment, a first conductive film 5006 made of a TaN film having a thickness of 30 [nm] and a second conductive film 5007 made of a W film having a thickness of 370 [nm] are formed by lamination. The TaN film was formed by a sputtering method, and was sputtered using a Ta target in an atmosphere containing nitrogen. The W film was formed by a sputtering method using a W target. Alternatively, it can be formed by a thermal CVD method using tungsten hexafluoride (WF ₆ ). In any case, it is necessary to lower the resistance in order to use it as a gate electrode.
It is desirable to set it to 0 [μΩcm] or less. The resistivity of the W film can be reduced by enlarging the crystal grains.
When there are many impurity elements such as oxygen in the film, crystallization is hindered and the resistance is increased. Therefore, in this embodiment, high-purity W
(Purity: 99.9999 [%]) by forming a W film with sufficient care so as not to mix impurities from the gas phase at the time of film formation by a sputtering method using a target having a resistivity of 9 to 9%. 20 [μΩcm] was achieved.

In this embodiment, the first conductive film 500
6 was TaN, and the second conductive film 5007 was W. However, there is no particular limitation, and any of Ta, W, Ti, Mo, Al, and C was used.
It may be formed of an element selected from u, Cr, and Nd, or an alloy material or a compound material containing the element as a main component. Alternatively, a semiconductor film typified by a polycrystalline silicon film doped with an impurity element such as phosphorus may be used. Also, A
An alloy composed of g, Pd, and Cu may be used. Further, the first conductive film is formed of a Ta film, the second conductive film is formed of a W film, and the first conductive film is formed of a TiN film.
The first conductive film is formed of a tantalum nitride (TaN) film, the second conductive film is formed of an Al film, the first conductive film is formed of a TaN film,
The second conductive film may be a combination of a Cu film.

Next, as shown in FIG. 5B, a mask 5008 made of a resist is formed by photolithography, and a first etching process for forming electrodes and wirings is performed. In the first etching process, the first and second
The etching conditions are as follows. In the present embodiment, as the first etching condition, ICP (Inductively Coupled Plasma:
Using an inductively coupled plasma) etching method, using CF ₄ , Cl _2, and O ₂ as etching gases, setting the respective gas flow ratios to 25/25/10 [sccm], and setting the coil at a pressure of 1 [Pa]. 500 [W] RF (13.56 [MH]
z]) Power was applied to generate plasma to perform etching. Here, a dry etching apparatus (Model E645-IC) using ICP manufactured by Matsushita Electric Industrial Co., Ltd.
P) was used. 150 [W] on substrate side (sample stage)
(13.56 [MHz]), and a substantially negative self-bias voltage is applied. The W film is etched under the first etching conditions to make the end of the first conductive layer tapered. The etching rate for W under the first etching condition is 200.39 [nm / min.], And TaN
Is 80.32 [nm / min.], And the selectivity ratio of W to TaN is about 2.5. Further, the taper angle of W is about 26 ° under the first etching condition.

Then, as shown in FIG. 5B, the second etching condition was changed without removing the resist mask 5008, and CF ₄ and Cl ₂ were used as etching gases, and the respective gas flow rates were changed. The ratio is 30/30 [sccm] and 1
At a pressure of [Pa], 500 [W] RF (1
3.56 [MHz]) power was supplied to generate plasma, and etching was performed for about 30 seconds. An RF (13.56 [MHz]) power of 20 [W] is also applied to the substrate side (sample stage), and a substantially negative self-bias voltage is applied. CF
_Under the second etching condition in which ₄ and Cl ₂ are mixed, both the W film and the TaN film are etched to the same extent. The etching rate for W under the second etching condition is 58.97 [n].
m / min.], and the etching rate for TaN is 66.43.
[nm / min.]. Note that in order to perform etching without leaving a residue on the gate insulating film, the etching time may be increased at a rate of about 10 to 20%.

In the first etching treatment, the shape of the mask 5008 made of resist is made appropriate, and the end of the first conductive layer and the second conductive layer is formed by the effect of the bias voltage applied to the substrate side. The portion has a tapered shape. The angle of the tapered portion may be 15 to 45 degrees. Thus, the first shape conductive layer 5009 including the first conductive layer and the second conductive layer by the first etching treatment.
To 5013 (first conductive layers 5009a to 5013a and second conductive layers 5009b to 5013b). In the gate insulating film 5005, the first shape conductive layer 50
The region not covered with 09 to 5013 is etched by about 20 to 50 [nm] to form a thinned region.

Then, a resist mask 5008 is formed.
The first doping process is performed without removing the impurity, and an impurity element imparting n-type is added to the semiconductor layer (FIG. 5B).
The doping treatment may be performed by an ion doping method or an ion implantation method. The condition of the ion doping method is that the dose amount is 1
× 10 ^{13 to} 5 × 10 ¹⁵ [atoms / cm ² ] and an acceleration voltage of 6
It is performed as 0 to 100 [keV]. In this embodiment, the dose is 1.5 × 10 ¹⁵ [atoms / cm ² ], and the acceleration voltage is 80 [keV].
Went as. Elements belonging to Group 15 as impurity elements imparting n-type, typically phosphorus (P) or arsenic (A
s), but phosphorus (P) was used here. In this case, the first shape conductive layers 5009 to 5012 serve as a mask for the impurity element imparting n-type, and self-aligned high-concentration impurity regions 5014 to 5016 are formed. 1 × 10 ²⁰ to 1 for high concentration impurity regions 5014 to 5016
An impurity element imparting n-type is added within a concentration range of × 10 ²¹ [atoms / cm ³ ].

Subsequently, as shown in FIG. 5C, a second etching process is performed without removing the resist mask 5008. Here, CF ₄ and C are used as etching gases.
Using l ₂ and O ₂ , the respective gas flow ratios were 20/20
/ 20 [sccm] and a pressure of 1 [Pa] to 5
RF (13.56 [MHz]) power of 00 [W] was supplied to generate plasma, and etching was performed. An RF (13.56 [MHz]) power of 20 [W] is also applied to the substrate side (sample stage), and a substantially negative self-bias voltage is applied.
The etching rate for W in the second etching process is 124. [nm / min.], the etching rate for TaN is 20. [nm / min.], and the selectivity ratio of W to TaN is 6.05. Therefore, the W film is selectively etched. By this second etching, the taper angle of W becomes 7
0 °. By this second etching process, second conductive layers 5017b to 5021b are formed. Meanwhile, the first
Of the conductive layers 5009a to 5013a are hardly etched to form first conductive layers 5017a to 5021a.

Next, a second doping process is performed. The doping is performed using the second conductive layers 5017b to 5020b as a mask for the impurity element, so that the semiconductor element below the tapered portion of the first conductive layer is doped with the impurity element. In this embodiment, P is used as the impurity element.
(Phosphorus) with a dose of 1.5 × 10 ¹⁴ [atoms / c
m ² ], a current density of 0.5 [μA], and an acceleration voltage of 90 [keV]. Thus, the low-concentration impurity regions 5022 to 5024 overlapping with the first conductive layer are formed in a self-aligned manner. These low-concentration impurity regions 5022 to 502
The concentration of phosphorus (P) added to 4 was 1 × 10 ^{17 to} 5 ×
10 ¹⁸ [atoms / cm ³ ], and has a gentle concentration gradient according to the thickness of the tapered portion of the first conductive layer.
Note that in the semiconductor layer overlapping with the tapered portion of the first conductive layer, the impurity concentration is slightly reduced from the end of the tapered portion of the first conductive layer toward the inside, but is approximately the same. . Further, the high-concentration impurity regions 5014 to
An impurity element is also added to 5016 (FIG. 6A).

Next, as shown in FIG. 6B, a third etching process is performed by using a photolithography method. A mask 5025 made of resist is formed in a region where the third etching is not performed. This third etching treatment is performed in order to partially etch the tapered portion of the first conductive layer so that the tapered portion overlaps with the second conductive layer.

Etching in Third Etching Process
The conditions are Cl as an etching gas. _TwoAnd SF₆Using
The first and second gas flow ratios were 10/50 [sccm].
And ICP etching method as in the second etching.
Do it. Note that TaN in the third etching process is
The etching rate is 111.2 nm / min.
The etching rate for the gate insulating film is 12.8 [nm / mi
n.].

In this example, etching was performed by applying a 500 [W] RF (13.56 [MHz]) power to the coil-type electrode at a pressure of 1.3 [Pa] to generate plasma. . The RF (13.56) of 10 [W] is also provided on the substrate side (sample stage).
[MHz]) Power is applied and a substantially negative self-bias voltage is applied. As described above, the first conductive layers 5026 a to 5026 a to 5
028a is formed.

By the third etching, impurity regions (LDD regions) 5029 to 5030 which do not overlap with the first conductive layers 5026a to 5028a are formed. Note that the impurity region (GOLD region) 5022 remains over the first conductive layer 5017a.

As described above, in this embodiment, the impurity region (L) which does not overlap with the first conductive layers 5026a to 5028a.
DD region) 5029 to 5030 and first conductive layer 501
The impurity region (GOLD region) 5022 overlapping with the gate electrode 7a can be formed at the same time, and can be separately formed according to the TFT characteristics.

Next, a mask 5025 made of resist is used.
Is removed, the gate insulating film 5005 is etched.
I do. Here, the etching process is performed by adding C to the etching gas.
HF _ThreeUsing reactive ion etching (RIE)
This is performed using In this embodiment, the chamber pressure is 6.7 [P
a], RF power 800 [W], CHF_ThreeGas flow rate 35 [sccm]
A third etching process was performed. This allows high concentrations
A part of the impurity regions 5014 to 5016 is exposed,
The insulating films 5005a to 5005d are formed.

Next, a new mask 50 made of resist is used.
31 is formed and a third doping process is performed. This third
Is obtained by adding an impurity element imparting a second conductivity type (p-type) opposite to the first conductivity type (n-type) to a semiconductor layer serving as an active layer of a p-channel TFT by the doping process. Regions 5032 to 5033 are formed. (FIG. 3
(C) Using the first conductive layer 5028a as a mask for an impurity element, an impurity element imparting p-type is added to form an impurity region in a self-aligned manner.

In this embodiment, the impurity regions 5032 to 5032
33 is formed by ion doping using diborane (B ₂ H ₆ ). In the third doping process, n
A semiconductor layer forming a channel type TFT is covered with a mask 5031 made of a resist. By the first doping process and the second doping process, the impurity region 50 is formed.
Phosphorus is added to 32 to 5033 at different concentrations, and the concentration of the impurity element imparting p-type is 2 × 10 ²⁰ to 2 × 10 ²¹ [atoms / c] in any of the regions.
By performing the doping treatment so as to be [m ³ ], there is no problem because it functions as the source region and the drain region of the p-channel TFT.

Through the above steps, impurity regions are formed in the respective semiconductor layers. In this embodiment, the method of doping the impurity (B) after etching the gate insulating film is described; however, the impurity may be doped without etching the gate insulating film.

Next, a mask 5031 made of resist is used.
Is removed to form a first interlayer insulating film 5 as shown in FIG.
No. 034 is formed. The first interlayer insulating film 5034 is formed of an insulating film containing silicon with a thickness of 100 to 200 [nm] by a plasma CVD method or a sputtering method. In this embodiment, the film thickness is 150
A [nm] silicon oxynitride film was formed. Needless to say, the first interlayer insulating film 5034 is not limited to a silicon oxynitride film, and another insulating film containing silicon may be used as a single layer or a stacked structure.

Next, a step of activating the impurity element added to each semiconductor layer is performed. This activation step is performed by a thermal annealing method using a furnace annealing furnace. As the thermal annealing method, the oxygen concentration is 1 [ppm] or less,
Preferably in a nitrogen atmosphere of 0.1 [ppm] or less,
The heat treatment may be performed at 700 ° C., typically 500 to 550 ° C. In this embodiment, the activation treatment is performed by heat treatment at 550 ° C. for 4 hours. In addition to the thermal annealing method, a laser annealing method or a rapid thermal annealing method (RTA)
Law) can be applied.

In this embodiment, at the same time as the activation process, the impurity regions (5014, 5015, 5032) containing high-concentration P containing Ni used as a catalyst during crystallization are used.
And the nickel concentration in the semiconductor layer which mainly becomes a channel formation region is reduced. A TFT having a channel formation region manufactured in this manner has a low off-current value and high crystallinity, so that a high field-effect mobility can be obtained and favorable characteristics can be achieved.

An activation process may be performed before forming the first interlayer insulating film 5034. However, when the wiring material used is weak to heat, after forming an interlayer insulating film 5034 (an insulating film containing silicon as a main component, for example, a silicon nitride film) to protect the wiring and the like as in this embodiment. Preferably, an activation treatment is performed.

Alternatively, a doping process may be performed after the activation process to form the first interlayer insulating film 5034.

Further, a heat treatment is performed in an atmosphere containing 3 to 100% of hydrogen at 300 to 550 ° C. for 1 to 12 hours to hydrogenate the semiconductor layer. In this embodiment, heat treatment was performed at 410 ° C. for one hour in a nitrogen atmosphere containing about 3% of hydrogen. In this step, dangling bonds in the semiconductor layer are terminated by hydrogen contained in the interlayer insulating film 5034. As another means of hydrogenation, plasma hydrogenation (using hydrogen excited by plasma) may be performed.

In the case where a laser annealing method is used as the activation treatment, it is desirable to irradiate a laser beam such as an excimer laser or a YAG laser after performing the above hydrogenation.

Subsequently, as shown in FIG. 7B, a flattening film 5035 made of an organic resin or the like is formed. In this embodiment, an acrylic film which is excellent in flattening is used, and is formed with a film thickness which can sufficiently flatten a step formed on a substrate by a TFT. Preferably, the thickness of the flattening film is 1 to 5 [μm].
(More preferably 2 to 4 [μm]).

Then, a contact hole is formed in the first insulating film 5034 and the flattening film 5035, and the wiring 5
036 to 5041 are formed. In this embodiment, a 50 nm thick Ti film and a 500 nm thick alloy film (Al
And an alloy film of Ti and Ti) are formed by patterning, but another conductive film may be used. At this time, a gate signal line 5042 is formed simultaneously with the same material as the wiring.

Next, a second interlayer insulating film 50 made of an insulating material containing silicon or an organic resin is formed by a plasma CVD method.
43 is formed. As the insulating material containing silicon, silicon oxide, silicon nitride, or silicon oxynitride can be used. As the organic resin, polyimide, polyamide, acrylic, BCB (benzocyclobutene), or the like can be used. Note that the thickness of the silicon oxynitride film is preferably 1 to 5 μm (more preferably 2 to 4 μm). A silicon oxynitride film is effective in suppressing deterioration of an EL element because moisture contained in the film itself is small.

Thereafter, a contact hole reaching the wiring 5037 is formed, and the cathode electrode 5044 of the photoelectric conversion element is formed.
To form In this embodiment, aluminum is used for this metal film by a sputtering method, but other metals, for example, Ti, Ta, W, Cu, etc. can be used. In addition, it may be formed not by a single layer but by a laminated structure including a plurality of metal films.

Next, an amorphous silicon film containing hydrogen is formed and patterned to form a photoelectric conversion layer 5045.
Subsequently, a cathode electrode 5046 made of a transparent conductive film is
Similarly, after the entire surface is formed, patterning is performed.

Next, as shown in FIG. 8A, a third interlayer insulating film 5047 is formed. Third interlayer insulating film 504
As 7, a flat surface can be obtained by using a resin such as polyimide, polyamide, polyimide amide, or acrylic. In this embodiment, the film thickness is 0.7 [μ
m] of the polyimide film was formed.

Next, after a contact hole reaching the wiring 5040 is formed, a transparent conductive film is formed with a thickness of 80 to 120 [nm], and is patterned to form a pixel electrode 50.
48 are formed (FIG. 8A). In this embodiment,
The pixel electrode 5048 includes indium tin oxide (IT
O) 2-20% zinc oxide (Z
A transparent conductive film mixed with nO) is used.

Next, an EL layer 5049 is formed by an evaporation method, and a cathode electrode (MgAg electrode) 505 is further formed by an evaporation method.
0 is formed. At this time, the EL layer 5049 and the cathode 5
It is desirable that heat treatment be performed on the pixel electrode 5048 before forming the 050 to completely remove moisture. In this example, Mg was used as the cathode electrode of the EL element.
Although an Ag electrode is used, other known materials may be used.

Note that a known material can be used for the EL layer 5049. In this embodiment, the hole transport layer (Ho
le transporting layer) and emitting layer (Emitting laye)
Although the two-layer structure of r) is an EL layer, any of a hole injection layer, an electron injection layer, and an electron transport layer may be provided. As described above, various examples of the combination have already been reported, and any of the configurations may be used.

In this embodiment, polyphenylene vinylene is formed as a hole transport layer by an evaporation method. Further, as the light emitting layer, a layer in which PBD of a 1,3,4-oxadiazole derivative is dispersed in 30 to 40% molecules in polyvinyl carbazole is formed by an evaporation method, and coumarin 6 is used as a green light emission center. 1% is added.

Further, in order to protect the EL layer 5049 from oxygen and moisture, it is desirable to form a protective film or the like. In this embodiment, 300 [n] is used as the passivation film 5051.
m] thick silicon nitride film. This passivation film 5
051 may also be formed continuously after formation of the cathode electrode 5050 without opening to the atmosphere.

The thickness of the EL layer 5049 is 10 to 40.
0 [nm] (typically 60 to 150 [nm]), the cathode electrode 50
The thickness of 50 is 80 to 200 [nm] (typically 100 to 1 nm).
50 [nm]).

In this way, E of the structure as shown in FIG.
The L module is completed. Note that EL in this embodiment is
In the manufacturing process of the module, the material forming the gate electrode is T due to the relationship between the circuit configuration and the process.
Although the source signal line is formed by a and W, and the gate signal line is formed by Al which is a wiring material forming the source and drain electrodes, different materials may be used.

FIG. 16 shows an example of a circuit arrangement of a pixel portion in a self-luminous device prepared according to the steps described in this embodiment. The numbers assigned to the respective parts are the same as those given in FIG. 4 which is an equivalent circuit. Α- in FIGS.
α ′, β−β ′, and γ−γ ′ correspond to the cross section of the same reference numeral in FIG.

According to this embodiment, a driver circuit including a TFT and the pixel portion shown in FIG. 8A can be formed over the same substrate.

In the present embodiment, the bottom emission (the light emission direction is on the TFT substrate side) is performed from the element configuration of the EL element, so that the switching TFT 413 is an n-channel TFT and the EL driving TFT 414 is a p-channel TFT. Type T
Although the configuration in which the FT is used has been described, the present embodiment is only a preferred embodiment and need not be limited to this.

In this embodiment, the structure is shown in which the EL layer 5049 is formed on the pixel electrode (anode) 5048 and then the cathode electrode 5050 is formed. However, the EL layer and the EL layer are formed on the pixel electrode (cathode). A structure in which an anode is formed may be used. At this time, the switching TFT and EL
The driving TFT is desirably formed of an n-channel TFT having a low-concentration impurity region (LDD region) described in this embodiment.

However, in this case, unlike the bottom emission described above (the emission light from the EL is applied to the active matrix substrate side on which the TFT is formed), a top emission form is adopted. An example is shown in FIG. In this case, the light receiving portion of the photoelectric conversion element also has a structure opposite to that of the present embodiment in accordance with the light emitting direction of the EL element. Further, the order of the steps is as follows: after forming the second interlayer insulating film 5043,
An L layer is formed, a third interlayer insulating film 5047 is formed, and then, a process sequence of forming a photoelectric conversion element is performed.

[Embodiment 6] Referring to FIG. The self-luminous device having the brightness correction function of the present invention can be easily applied even when the display device supports an analog video signal. In such a case, the second video signal (digital video signal) output from the correction circuit 1305 is converted into an analog video signal by the D / A conversion circuit 1314, and the display device 1308 corresponding to the analog video signal. And an image is displayed.

FIG. 14B is a circuit diagram of a source signal line driver circuit in the display device 1308 in FIG.
Here, a display device corresponding to an analog video signal is taken as an example. The source signal line driving circuit includes a shift register (SR) 1411, a level shifter 1412, a buffer 1
413, a sampling switch 1414, and the like. 1
Reference numeral 415 is a pixel, 1416 is a luminance correction device shown in FIG. 13, and 1417 is a D / A conversion circuit.

The operation of each section will be described. According to a clock signal (CLK) and a start pulse (SP),
Sampling pulses are sequentially output from the shift register. After that, the voltage amplitude of the pulse is expanded by the level shifter and output via the buffer. The digital video signal is corrected by a luminance correction device, converted into an analog video signal by a D / A conversion circuit, and input to a video signal line. Thereafter, the sampling switch is opened according to the timing of the sampling pulse, the analog video signal input to the video signal line is sampled, and the voltage information is written to the pixel to display an image.

In the example shown in FIG. 13, the brightness correction device is provided outside the display device. However, as described in the fourth embodiment, these devices may be integrally formed on the same substrate.

[Embodiment 7] In the present invention, by using an EL material capable of utilizing phosphorescence from triplet excitons for emission, external light emission quantum efficiency can be remarkably improved. As a result, the power consumption and the life of the EL element can be reduced,
And weight reduction becomes possible.

Here, a report is shown in which the triplet exciton is used to improve the external light emission quantum efficiency. (T.Tsutsui, C.Adachi, S.Saito, Photochemical Proc
esses in Organized Molecular Systems, ed.K. Honda,
(Elsevier Sci. Pub., Tokyo, 1991) p.437.) EL material (coumarin dye) reported in the above paper
Is shown below.

[0138]

Embedded image

(MABaldo, DFO'Brien, Y. You, A. Sho
ustikov, S. Sibley, METhompson, SRForrest, Natu
re 395 (1998) p.151.) The molecular formula of the EL material (Pt complex) reported by the above paper is shown below.

[0140]

Embedded image

(MABaldo, S. Lamansky, PEBurrrows,
METhompson, SRForrest, Appl.Phys.Lett., 75 (19
99) p.4.) (T.Tsutsui, M.-J.Yang, M.Yahiro, K.Nakamura, T.Wa
tanabe, T.tsuji, Y.Fukuda, T.Wakimoto, S.Mayaguch
i, Jpn. Appl. Phys., 38 (12B) (1999) L1502.) The molecular formula of the EL material (Ir complex) reported by the above-mentioned paper is shown below.

[0142]

Embedded image

As described above, if the phosphorescence emission from the triplet exciton can be used, it is possible in principle to realize an external emission quantum efficiency three to four times higher than the case where the fluorescence emission from the singlet exciton is used. . Note that the configuration of this embodiment is the same as that of Embodiments 1 to
It is possible to freely combine and implement any of the configurations of the sixth embodiment.

[Eighth Embodiment] An EL display to which the self-luminous device of the present invention is applied is excellent in visibility in a bright place and has a wide viewing angle as compared with a liquid crystal display since it is a self-luminous type. Therefore, it can be used as a display portion of various electronic devices.

The EL display includes all information display devices such as a personal computer display device, a TV broadcast reception display device, and an advertisement display device. In addition, the self-luminous device of the present invention can be used for display portions of various electronic devices.

[0146] Such electronic devices of the present invention include a video camera, a digital camera, a goggle type display device (head mounted display), a navigation system,
Sound playback devices (car audio, audio components, etc.), notebook personal computers, game machines,
A portable information terminal (a mobile computer, a mobile phone, a portable game machine, an electronic book, or the like), an image reproducing apparatus provided with a recording medium (specifically, a digital video disc (DV
D) and the like, a device having a display capable of reproducing a recording medium and displaying its image). In particular, for a portable information terminal that is often viewed from an oblique direction, a wide viewing angle is regarded as important, so it is desirable to use an EL display. FIGS. 11 and 12 show specific examples of these electronic devices.
Shown in

FIG. 11A shows an EL display.
A housing 3301, a support 3302, a display portion 3303, and the like are included. The self-luminous device of the present invention can be used for the display portion 3303. Since the EL display is a self-luminous type, it does not require a backlight and can be a display portion thinner than a liquid crystal display.

FIG. 11B shows a video camera, which includes a main body 3311, a display section 3312, an audio input section 3313, operation switches 3314, a battery 3315, and an image receiving section 331.
6 and so on. The self light emitting device of the present invention can be used for the display portion 3312.

FIG. 11C shows a part (one side on the right) of the head-mounted EL display.
24, an optical system 3325, a display device 3326, and the like. The self light emitting device of the present invention can be used in the display device 3326.

FIG. 11D shows an image reproducing apparatus (specifically, a DVD reproducing apparatus) provided with a recording medium.
1, recording medium (DVD, etc.) 3332, operation switch 33
33, a display unit (a) 3334, a display unit (b) 3335, and the like. The display unit (a) 3334 mainly displays image information, and the display unit (b) 3335 mainly displays character information.
34, the display portion (b) 3335 can be used.
Note that the image reproducing device provided with the recording medium includes a home game machine and the like.

FIG. 11E shows a goggle type display device (head mounted display), which includes a main body 3341, a display portion 3342, and an arm portion 3343. The self-luminous device of the present invention can be used for the display portion 3342.

FIG. 11F shows a personal computer, which includes a main body 3351, a housing 3352, a display portion 3353,
A keyboard 3354 and the like. The light emitting device of the present invention can be used in the display portion 3353.

If the emission luminance of the EL material becomes high in the future, it becomes possible to enlarge and project the light containing the output image information with a lens or the like and use it for a front-type or rear-type projector.

Further, the above-mentioned electronic equipment is available on the Internet or C
Information distributed through an electronic communication line such as an ATV (cable television) is often displayed, and in particular, opportunities to display moving image information are increasing. Since the response speed of the EL material is very high, the EL display is preferable for displaying moving images.

In an EL display, a light emitting portion consumes power. Therefore, in order to save power, it is desirable to display information so that the light emitting portion is reduced as much as possible. Therefore, when an EL display is used for a portable information terminal, particularly a display unit mainly for text information such as a mobile phone or a sound reproducing device, the display is driven so that text information is formed by a light-emitting portion with a non-light-emitting portion as a background. It is desirable to do.

FIG. 12A shows a portable telephone, and the main body 34 is provided.
01, audio output unit 3402, audio input unit 3403, display unit 3404, operation switch 3405, antenna 3406
including. The self-luminous device of the present invention can be used for the display portion 3404. Note that the display portion 3404 can reduce power consumption of the mobile phone by displaying white characters on a black background.

FIG. 12B shows a sound reproducing apparatus, specifically, a car audio.
2. Including operation switches 3413 and 3414. The self-luminous device of the present invention can be used for the display portion 3412.
In this embodiment, the in-vehicle audio is shown, but the present invention may be applied to a portable or home-use audio reproducing apparatus. Note that the display portion 3414 can suppress power consumption by displaying white characters on a black background. This is particularly effective in a portable sound reproducing device.

FIG. 12C shows a digital camera, which includes a main body 3501, a display section (A) 3502, an eyepiece section 3503,
An operation switch 3504, a display portion (B) 3505, and a battery 3506 are included. The electro-optical device of the invention can be used for the display portion (A) 3502 and the display portion (B) 3505.

As described above, the applicable range of the present invention is extremely wide, and the present invention can be used for electronic devices in various fields. In addition, any of the configurations shown in the first to seventh embodiments may be applied to the electronic device of the present embodiment.

According to the self-luminous device of the present invention, there is provided a self-luminous device capable of correcting a lack of luminance due to deterioration of an EL element or other causes on the circuit side and displaying a uniform screen without luminance unevenness. I can do it.

[Brief description of the drawings]

FIG. 1 is a block diagram of a self-luminous device having a luminance detection and correction function of the present invention.

FIG. 2 is a diagram showing a correction method by an addition process.

FIG. 3 is a diagram showing a correction method by a subtraction process.

FIG. 4 is a block diagram of a display device and an equivalent circuit diagram of a pixel portion in a self-luminous device having a luminance detection and correction function of the present invention.

FIG. 5 is a diagram showing an example of a manufacturing process of an active matrix self-luminous device.

FIG. 6 is a diagram illustrating an example of a manufacturing process of an active matrix self-luminous device.

FIG. 7 is a diagram showing an example of a manufacturing process of an active matrix self-luminous device.

FIG. 8 is a diagram showing an example of a manufacturing process of an active matrix type self-luminous device.

FIG. 9 illustrates a time gray scale method.

FIG. 10 is a view showing the occurrence of luminance unevenness on a screen due to deterioration of a self-luminous element.

FIG. 11 is a diagram showing an application example of a self-luminous device having a luminance detection and correction function of the present invention to electronic equipment.

FIG. 12 is a diagram showing an application example of a self-luminous device having a luminance detection and correction function of the present invention to electronic equipment.

FIG. 13 is a block diagram of a self-luminous device having a luminance detection and correction function according to the present invention.

FIG. 14 is a block diagram of a source signal line drive circuit of a digital video signal input method and an analog signal input method in a self-luminous device having a luminance detection and correction function of the present invention.

FIG. 15 illustrates an example of a conventional self-luminous device.

FIG. 16 is a diagram showing an example of a wiring pattern of a pixel portion in a self-luminous device having a luminance detection and correction function of the present invention.

FIG. 17 is a diagram illustrating an example of a manufacturing process of an active matrix self-luminous device.

FIG. 18 is a cross-sectional view of Japanese Patent Application No. 2000-273139.
FIG. 4 is a block diagram of a self-luminous device having a correction function.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09G 3/20 670 G09G 3/20 670J 680 680H H05B 33/08 H05B 33/08 33/14 33/14 A

Claims (24)

[Claims] 1. A self-luminous device for displaying a video by inputting a video signal, comprising: means for detecting the luminance of a self-luminous element of each pixel; means for storing the luminance; Means for correcting the video signal, wherein a video is displayed using the corrected video signal. 2. A self-luminous device for displaying an image by inputting a video signal, comprising: a photoelectric conversion element for detecting a luminance of a self-luminous element of each pixel; and a self-luminous light of each pixel detected by the photoelectric conversion element. A storage circuit for storing the luminance of the element, and a first circuit corresponding to the stored luminance of the self-luminous element of each pixel.
A signal correction unit that corrects the video signal and outputs a second video signal; and a display device that displays a video using the second video signal. Self-luminous device. 3. A self-luminous device for displaying a video by inputting a video signal, wherein j × k (j, k,
k is a natural number), storage for storing the luminance of the self-luminous element of each pixel detected by the photoelectric conversion element, and a first value according to the stored luminance of the self-luminous element of each pixel.
A brightness correction device having a signal correction unit that corrects the video signal and outputs a second video signal. J × k that displays video using the second video signal.
And a display device having pixels. 4. The self-luminous device according to claim 1, wherein the self-luminous device that performs n-bit (n is a natural number, n ≧ 2) gray scale display comprises n + m bits ( m is a natural number), a pixel having a self-luminous element that does not cause a decrease in luminance
To perform gradation display using an n-bit video signal, and to correct the n-bit video signal using an m-bit signal for a pixel having a self-luminous element that has reduced luminance. A self-luminous device characterized in that the same luminance is obtained between the self-luminous element that has not caused the decrease in luminance and the self-luminous element that has caused the decrease in luminance. 5. The self-luminous device according to claim 1, wherein said correcting means comprises: a video signal written to a pixel having a self-luminous element having reduced luminance; A self-luminous device, which performs a relative addition process on a video signal written to a pixel having a self-luminous element in which a decrease in luminance has not occurred. 6. The self-luminous device according to claim 1, wherein said correcting means comprises a pixel having a self-luminous element having a small decrease in luminance or a decrease in luminance within a display range. A video signal written to a pixel having a self-luminous element that does not cause a luminance is subjected to a relative subtraction process with respect to a video signal written to a pixel having a self-luminous element having the largest decrease in luminance. Self-luminous device. 7. The self-luminous device according to claim 1, wherein said storage means uses a static memory circuit (SRAM). 8. The self-luminous device according to claim 1, wherein said storage means uses a dynamic memory circuit (DRAM). 9. The self-luminous device according to claim 1, wherein said storage means uses a ferroelectric memory circuit (FeRAM). 10. The self-luminous device according to claim 1, wherein said storage means uses a nonvolatile memory (EEPROM) which can be electrically written, read and erased. Features a self-luminous device. 11. The self-luminous device according to claim 1, wherein a PN-type photodiode is used for said photoelectric conversion element as said luminance detecting means. apparatus. 12. The self-luminous device according to claim 1, wherein said photoelectric conversion element includes a PIN as said luminance detecting means.
A self-luminous device using a type photodiode. 13. The self-luminous device according to claim 1, wherein an avalanche photodiode is used for said photoelectric conversion element as said luminance detecting means. apparatus. 14. The self-luminous device according to claim 1, wherein said detecting means, said storing means, and said correcting means comprise:
A self-luminous device comprising a circuit external to the self-luminous device. 15. The self-luminous device according to claim 1, wherein said detecting means, said storing means, and said correcting means comprise:
A self-luminous device formed on the same insulator as the self-luminous device. 16. The self-luminous device according to claim 1, wherein said self-luminous device is an EL display. 17. The self-luminous device according to claim 1, wherein said self-luminous device is a PDP display. 18. The self-luminous device according to claim 1, wherein said self-luminous device is an FED display. 19. A method of driving a self-luminous device for displaying a video by inputting a video signal, comprising detecting a luminance of a self-luminous element of each pixel, and storing the detected luminance of the self-luminous element of each pixel. And correcting the first video signal in accordance with the stored difference between the luminance of the self-luminous element of each pixel and the reference luminance, outputting a second video signal, and outputting the second video signal. A method for driving a self-luminous device, comprising: displaying an image by using the method. 20. A method of driving a self-luminous device for displaying an image by inputting a video signal, comprising detecting a luminance of a self-luminous element of each pixel by a photoelectric conversion element, and detecting the luminance by the photoelectric conversion element. The luminance of the self-luminous element of each pixel is stored in a storage circuit, and the first image is stored in the signal correction unit according to the difference between the luminance of the self-luminous element of each pixel and the reference luminance stored in the storage circuit. A method for driving a self-luminous device, comprising: correcting a signal, outputting a second video signal, and displaying a video using the second video signal. 21. A driving method for a self-luminous device according to claim 19 or claim 20, wherein the self-luminous device that performs n-bit (n is a natural number, n ≧ 2) gray scale display has n + m bits (m is A pixel having a self-luminous element that has a drive circuit that performs signal processing of
The gradation display is performed by the n-bit video signal, and for the pixel having the self-luminous element in which the luminance is reduced, the video signal is corrected by using the m-bit signal with respect to the n-bit video signal. A method of driving the self-luminous device, wherein the same luminance is obtained between the self-luminous element that has not caused the decrease in luminance and the self-luminous element that has caused the decrease in luminance. 22. One of claims 19 to 21.
In the driving method of the self-luminous device according to the item, the correction means includes a pixel having a self-luminous element in which the luminance does not decrease, in a video signal written to a pixel having the self-luminous element in which the luminance has decreased. A driving method for a self-luminous device, wherein an addition process is relatively performed on a video signal written to the self-luminous device. 23. Any one of claims 19 to 21.
In the driving method of the self-luminous device according to the item, the correction means is written in a pixel having a self-luminous element with a small decrease in luminance or a pixel having a self-luminous element with no luminance decrease within a display range. A method of driving a self-luminous device, comprising: performing a relative subtraction process on a video signal written to a pixel having a self-luminous element with the largest decrease in luminance. 24. An electronic apparatus using the self-luminous device or the method for driving a self-luminous device according to claim 1. Description: